JPH04170820A - Semiconductor integrated circuit device - Google Patents

Abstract

PURPOSE:To prevent the increase of power consumption without causing the problem of the variation of a level by turning an analog switch conductive or non-conductive by a control signal, and storing this conductive or non- conductive state in a register, and making the analog switch non-energizable after the completion of storage. CONSTITUTION:An analog switch group 80 consisting of the analog switches 81 to 83 constituted of MOS transistors instead of fuses is connected in series to resistors 51 to 53 respectively. Besides, the junctions 111 to 113 of the analog switches 81 to 83 and the resistors 51 to 53 are made the inputs of a register group 90 consisting of registers 91 to 93. A control means 100 generates the control signal for making the analog switches 81 to 83 energizable or non- energizable, and further, for writing the signal of the 'high' level or the 'low' level of the junctions 111 to 113 to the registers 91 to 93. Thus, the 'high' level can be transmitted surely without causing the malfunction of a succeeding stage, and in addition, the increase of the power consumption can be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] Regarding the semiconductor integrated circuit device of the present invention, in particular, an analog method for selecting an optimal resistance group from a plurality of resistances in order to generate a highly accurate reference voltage. The present invention relates to a semiconductor integrated circuit device that uses a switch.

[Conventional technology]

A conventional semiconductor integrated circuit device of this type has the configuration shown in FIG.

FIG. 2 is a circuit diagram of a semiconductor integrated circuit device for supplying a reference voltage. In FIG. 2, this semiconductor device is formed as a plurality of diffused resistor groups 10 divided into connection points 11 to 18 in a semiconductor substrate, and the connection points of these resistances are connected in a cascade. It is connected to the second input terminal of the operational amplifier 2 via the MOS transistors 41 to 48, 31 to 34, and 21.22.

This operational amplifier 2 includes a first input terminal 1 for an input signal and an output terminal 3 for supplying a reference voltage, and one end of a diffused resistor is connected to the output terminal 3. - One end of the fuses 71, 72.73 for resistor trimming is grounded, and the other end is connected to the resistor 51, 52.53, respectively.
It is connected to the power supply terminal 4 via. The connection points of the fuses 71°72.73 and the resistors 51, 52.53 are connected to the input terminals of the inverters 8L 62, 63 and MO
S transistor 21, 31, 33, 41.43.45,
The inverters 61, 62 .
The output terminal of 83 is the MOS transistor 22, 32.3
4, 42, 44°48.48. Further, these elements are integrated within the same chip.

Now, if we consider a state in which none of the fuses 71, 72, and 73 are disconnected, in this state, the connection point between the fuse and the resistor is at the "low" level, so the even numbered MOS transistors are All those with odd numbers are in a conductive state, and all the odd numbered ones are in a non-conductive state. Therefore, in this state, the second input terminal of the operational amplifier 2 is connected to the resistor connection point 18 via the MOS transistors 22, 34, 48. If the fuse 73 is cut here, the MOS transistors 42, 44 .
48 and 48 become non-conductive, and the MOS transistor 41
, 43, 45.47 turns into conduction. Therefore, the second input terminal of the operational amplifier 2 is connected to the MOS transistors 22 and 34.
．． It will be connected to the connection point 17 via 47. By selecting whether or not to disconnect each fuse in this way, the second input terminal of the operational amplifier 2 is connected to the connection point 1 of the resistor.
1 to 18 can be connected.

Therefore, in the conventional trimming method, after manufacturing the semiconductor integrated circuit device, various characteristics are measured and the point to be connected to the second input of the operational amplifier 2 is determined from among the connection points 11 to 18. and had cut the fuse that made it possible.

[Problem to be solved by the invention]

In the conventional semiconductor integrated circuit device described above, the fuse 7 is connected in series with the current limiting resistors 51, 52, and 53 for trimming.
1.72.73 is required (the value of this current limiting resistor is R1). Therefore, if the resistance of the fuse after the fuse is cut is R2, then the voltage at the input of the inverter in the next stage of the fuse and the gate input of the MOS transistor is (VXR2)/(R1+R2) (hereinafter, this voltage is vl).

If the fuse is now incompletely blown and R2 no longer has a sufficiently high resistance compared to R1, vl will be lower than the threshold voltage VT of the next stage inverter and MOS transistor, and Vl will originally be at the "No. 1" level. It ends up being at a “low” level where it should be. Therefore, if the resistor R1 is made smaller, a large current flows in the fuses that are not cut, increasing power consumption.

Therefore, the object of the present invention is to first use an analog switch instead of using a fuse, and to make the analog switch conductive and non-conductive using a control signal, thereby ensuring that the next stage is ")1". level or "low" level.Secondly, the conduction/nonconduction state of the analog switch is stored in a register, and after the memorization is completed, the analog switch is made nonconductive to prevent an increase in dissipated power. An object of the present invention is to provide a semiconductor integrated circuit device.

[Means to solve the problem]

The semiconductor integrated circuit device of the present invention has a configuration including a series body of a plurality of resistors, an analog switch connected to a common connection point of the plurality of resistors and used for trimming the resistance value of the resistor, and an analog switch for trimming the resistance value of the resistor. A register that stores the conduction or non-conduction state of the analog switch so as to determine a result, and a control means that determines the conduction or non-conduction of the analog switch and stores the conduction or non-conduction state of the analog switch in the register. It is characterized by having the following.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a circuit diagram showing a semiconductor integrated circuit device according to an embodiment of the present invention.

In this figure, parts that are the same as those of the conventional example shown in FIG. 2 are given the same reference numbers, so detailed explanations of those parts will be omitted.

In this embodiment, an analog switch group 80 consisting of analog switches 81, 82, and 83 each constructed of a MOS transistor instead of a fuse is connected in series with the resistors 51, 52, and 53, respectively. Also, the connection points 111, 112, 113 between the analog switches 81, 82, 83 and the resistors 51, 52, 53 are connected to the registers 91, 92, 9.
It serves as an input to a register group 90 consisting of three registers.

The control means 100 includes analog switches 81, 82, 83.
Furthermore, connection points 111 and 11 are connected in order to conduct or non-conduct.
2,113 "high" level or "low" level signal is a control means for creating a control signal for writing into register θ1, 92°93, and signal 101 is connected to connection point 111, 112.
, 113 to the registers 9L 82, 93, and the signals 102, 103, 104
is a control signal for making the analog switches 81, 82, 83 conductive or non-conductive.

Next, an operation corresponding to conventional fuse cutting will be explained.

Description will be made assuming that in the conventional FIG. 2, only the fuse 71 is cut, but the fuses 72 and 73 are not cut.

To accomplish this in FIG. 1, control signal 104 is inactive and control signals 103, 102 are active. At this time, the analog switch 81 is non-conductive, the analog switches 82 and 83 are conductive, the connection point 111 is at a "high" level, and the connection points 112 and 113 are at a "low" level. Further, the levels of the connection points 111, 112, 113 are written to the registers 91, 92, 93 by the control signal 101. After writing to the register, the control signal 101
becomes inactive, data writing to registers 91, 92, and 93 is prohibited, and control signals 102, 103, and
104 is also inactive, and analog switches 81, 82 .
83 are all non-conductive, and the current flowing through the resistors 51, 52, and 53 becomes extremely small, making it possible to reduce power consumption.

Therefore, in this embodiment, by using an analog switch instead of a fuse, a reliable "high" level can be transmitted to the next stage without malfunction, and the signal can be transmitted to the register 91.
, 92, 93, and then analog switch 8
By making 1, 82, and 83 non-conductive, an increase in power consumption can be prevented.

〔Effect of the invention〕

As explained above, the semiconductor integrated circuit device of the present invention includes
Since an analog switch is used instead of using a fuse, the analog switch can be made conductive by the control signal.
It is possible to make the analog switches non-conductive, so there is no problem of level fluctuations such as faulty fuses, and the information on whether analog switches are conductive or non-conductive is stored in a register, and after memorization, all analog switches are made non-conductive. Therefore, it is possible to prevent an increase in power consumption, and so on.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a semiconductor integrated circuit device according to an embodiment of the present invention.
Input terminal, 2... operational amplifier, 3... output, 4...
・Power terminal, 10... Resistor group, 11-18... Connection point, 21, 22. 31-34. 41-48... Enhancement MO8) transistor, 61-63... Inverter, 71-73 ...Fuse, 8o...Analog switch group, 81-83...Analog switch, 9
0...Register group, 91-93...Register, 10
0... Control means, 101-... Register write signal, 102, 103. 104... Analog switch control signal, 111, 112, 113... Connection point, 51.5
2.53...Current limiting resistance.

Claims (1)

[Claims] a series body of a plurality of resistors, an analog switch connected to a common connection point of the plurality of resistors and used for trimming the resistance value of the resistor, and conduction of the analog switch so as to determine the trimming result; A semiconductor integrated circuit comprising: a register that stores a non-conducting state; and a control means that determines whether the analog switch is conductive or non-conductive and stores the conductive or non-conductive state of the analog switch in the register. circuit device.